1. Field of the Invention
The present invention relates to sleep monitoring systems, and particularly to a breathing disorder treatment system and method that provides a continuous monitoring and an actuated stimulation system for the treatment of sleep disorders, such as sleep apnea, and other medical disorders and conditions that adversely affect a patient's breathing.
2. Description of the Related Art
Sleep apnea is a sleep disorder characterized by pauses in breathing during sleep. Each episode, referred to as an “apnea”, lasts long enough so that one or more breaths are missed, and such episodes occur repeatedly throughout sleep. The standard definition of any apnea event includes a minimum ten second interval between breaths, with either a neurological arousal, a blood oxygen desaturation of 3 to 4% or greater, or both arousal and desaturation. Sleep apnea is typically diagnosed by an overnight sleep test called a polysomnogram. Sleep apnea not only affects the sufferer, but due to snoring and other noises associated with apnea, others in the vicinity of the sleeper may be adversely affected due to the disturbed sleep.
Clinically significant levels of sleep apnea are defined as five or more episodes per hour of any type of apnea (determined by the polysomnogram). There are three distinct forms of sleep apnea, including central, obstructive, and complex (i.e., a combination of central and obstructive), constituting 0.4%, 84% and 15% of cases, respectively. Breathing is interrupted by the lack of respiratory effort in central sleep apnea. In obstructive sleep apnea, breathing is interrupted by a physical block to airflow despite respiratory effort. In complex (or “mixed”) sleep apnea, there is a transition from central to obstructive features during the events themselves.
The most common treatment for obstructive sleep apnea is the use of a continuous positive airway pressure (CPAP) device, which “splints” the patient's airway open during sleep via a flow of pressurized air into the throat. Such systems, however, are rather bulky and uncomfortable for the user. Until the user becomes accustomed to the CPAP device, he or she may be kept awake by the machine that is designed to aid him or her in sleeping properly.
In addition to CPAP, a dentist specializing in sleep disorders may prescribe Oral Appliance Therapy (OAT). The oral appliance is a custom-made mouthpiece that shifts the lower jaw forward, which opens up the airway. OAT is usually successful in patients with mild to moderate obstructive sleep apnea, but can cause tempomendibular joint disfunction, loosening or breakage of teeth, veneers, crowns, caps, and implants. As with CPAP, the OAT may prevent the user from gaining a good night's sleep until he or she becomes accustomed to the awkwardness of the device. It should be noted that CPAP and OAT are effective only for obstructive sleep apnea, not for central or mixed cases.
For patients who do not tolerate or who fail non-surgical measures, surgical treatment to anatomically alter the airway is available. Several levels of obstruction may be addressed, including the nasal passage, throat (pharynx), base of tongue, and facial skeleton. Surgical treatment for obstructive sleep apnea needs to be individualized in order to address all anatomical areas of obstruction. Often, correction of the nasal passages needs to be performed, in addition to correction of the oropharynx passage.
Septoplasty and turbinate surgery may improve the nasal airway. Tonsillectomy and uvulopalatopharyngoplasty (UPPP or UP3) is available to address pharyngeal obstruction. Base of tongue advancement by means of advancing the genial tubercle of the mandible may help with the lower pharynx. A myriad of other techniques are available, including hyoid bone myotomy and suspension and various radiofrequency technologies. For patients who fail these operations, the facial skeletal may be advanced by means of a technique called maxillo-mandibular advancement, or two-jaw surgery (upper and lower jaws). The surgery involves a Lefort type one osteotomy and bilateral sagittal split mandibular osteotomies. Such severe treatments, however, come with the typical risks and discomforts of major surgery.
It should be noted that sleep apnea is not simply an inconvenience for the sufferer. Many drugs and agents used during surgery to relieve pain and to depress consciousness remain in the body at low amounts for hours or even days afterwards. In an individual with either central, obstructive or mixed sleep apnea, these low doses may be enough to cause life-threatening irregularities in breathing.
Use of analgesics and sedatives in these patients postoperatively should therefore be minimized or avoided. Surgery on the mouth and throat, as well as dental surgery and procedures, can result in postoperative swelling of the lining of the mouth and other areas that affect the airway. Even when the surgical procedure is designed to improve the airway, such as tonsillectomy and adenoidectomy or tongue reduction, swelling may negate some of the effects in the immediate postoperative period. Once the swelling resolves and the palate becomes tightened by postoperative scarring however, the full benefit of the surgery may be noticed. Individuals with sleep apnea generally require more intensive monitoring after surgery for these reasons.
For the complex variety of other respiratory ailments, each is specifically treated as needed with antibiotics, supplemental oxygen, aerobic exercise, corticosteroids, short-term use of ventilators or a host of other treatment options. Benefits from these treatments must be monitored for their effectiveness. A common symptom for respiratory distress is lower than required blood oxygen. Thus, a blood oxygen saturation (BOS) monitoring and treatment system would be beneficial for providing an early warning when measured BOS equals or is below a set value. Thus, a breathing disorder treatment system and method solving the aforementioned problems is desired.